I can't seem to sustain an erection while having sex and im 23?

Many causes: Ed is a very common in males. However, in a 23 year old, a workup is warranted to find a treatbale cause. This may be due to a physical cause or psychological factors. Causes may include varicocele, hypogonadism, or hormonal imbalance. Routine blood studies and a physical examination will identify potential problems and help tailor a specific treatment.